In recent years, as applications of display products become more widely, the studies for display technology also have become more deeply. As a new manufacturing process, LTPS (Low Temperature Poly-Silicon) technology utilizes an excimer laser annealing process to convert an amorphous silicon (a-Si) layer into a poly-silicon (poly-Si) thin film layer. Compared with an amorphous silicon material, a poly-silicon material has increased electron mobility by 100 times or more; therefore, the use of LTPS technology can achieve faster response time, higher resolution and better screen-display quality. Moreover, the use of LTPS technology can reduce integration circuits, simplify periphery of a display device, and implement a narrow-frame technique.
FIG. 1 presents an array-substrate intermediate structure employing LTPS, and as illustrated in FIG. 1, the intermediate structure comprises: a substrate 1, a low-temperature poly-silicon layer 2, a gate insulating layer 3, a gate metal layer 4, an interlayer insulating layer 5 and source-drain via-holes 6, etc. For preparation of the above-described array-substrate intermediate structure, via-holes as illustrated in FIG. 1 are formed, and typically, the etching for the via-holes is accomplished by dry etching or wet etching in a conventional etching method.